Climate Control and Ozone Depletion Chapter 19. An Enormous Cloud of Air Pollutants and Ash from Iceland volcano (April 2010) This dust cloud closed Airports.

Climate Control and Ozone Depletion

Chapter 19

An Enormous Cloud of Air Pollutants and Ash from Iceland volcano (April 2010)

This dust cloud closedAirports in Europe foralmost one week.

Coal Power Plant emitting green house gas

19-1 How Might the Earth’s Temperature and Climate Change in the Future?

Concept 19-1 The overwhelming scientific consensus is that the earth’s atmosphere is warming rapidly, mostly because of human activities, and that this will lead to significant climate change during this century.

How Do We Know What Temperatures Were in the Past?

Scientists analyze tiny air bubbles trapped in ice cores learn about past:• troposphere

composition. • temperature trends.• greenhouse gas

concentrations.• solar, snowfall, and

forest fire activity.

Estimated Changes in the Average Global Temperature of the Atmosphere

Fig19-2

Carbon Dioxide at highest levels

In 2005, an ice core showed that CO2 levels in the troposphere are the highest they have been in 650,000 years.

The Natural Greenhouse Effect Four major factors shape the earth’s climate:• The sun.• Greenhouse effect that warms the earth’s lower

troposphere and surface because of the presence of greenhouse gases.

• Oceans store CO2 and heat, evaporate and receive water, move stored heat to other parts of the world.

• Natural cooling process through water vapor in the troposphere (heat rises).

Atmospheric Levels of CO2 and CH4, Global Temperatures, and Sea Levels

Fig 19-4

Keeling Curve

IPCC greenhouse gases by source

Carbon Dioxide Trends (IPCC)

Animation: Greenhouse effect

The Atmosphere Is Warming Mostly Because of Human Activities

Intergovernmental Panel on Climate Change (IPCC)• 90–99% likely that lower atmosphere is warming• 1906–2005: Ave. temp increased about 0.74˚C• 1970–2005: Annual greenhouse emissions up 70%• Past 50 years: Arctic temp rising almost twice as fast as the rest

of the earth• Melting of glaciers and floating sea ice• Prolonged droughts: increasing• Last 100 years: sea levels rose 10–20 cm• Warmer temperatures in Alaska, Russia, and the Arctic are

melting permafrost releasing more CO2 and CH4 into the troposphere.

Melting of Alaska’s Muir Glacier between 1948 and 2004

The Big Melt: Some of the Floating Sea Ice in the Arctic Sea

The Scientific Consensus about Future Climate Change

There is strong evidence that human activities will play an important role in changing the earth’s climate during this century.• Coupled General Circulation Models (CGCMs)

couple, or combine, the effects of the atmosphere and the oceans on climate.

Fig. 19-A, p. 502

Sun

Troposphere

Cooling from increase

Aerosols Greenhouse gases Warming

from decrease

CO2 removal by plants and soil organisms

CO2 emissions from land clearing, fires, and decay

Heat and CO2 removal

Heat and CO2 emissions

Ice and snow cover

Shallow ocean

Land and soil biotaLong-term storageNatural and human

emissions

Deep ocean

CGC Models sources

NASA

IPCC Climate Change Model

Comparison of Measured Temperature from 1860–2007 and Projected Changes

Fig 19-b

Intergovernmental Panel on Climate Change (IPCC)Fourth Assessment Report 2007

Click for IPCC web page

Warming of the climate system is unequivocal, as isnow evident from observations of increases in globalaverage air and ocean temperatures, widespreadMelting of snow and ice and rising global average sea level(Figure SPM.1). {1.1}Most of the observed increase in global averageTemperatures since the mid-20th century is verylikely (p = .90) due to the observed increase in anthropogenic GHG concentrations.(Figure SPM.4). {2.4}

IPCC Treatment of Uncertainty

Where uncertainty is assessed more quantitatively usingexpert judgment of the correctness of underlying data, models or analyses, then the following scale of confidencelevels is used to express the assessed chance of a finding being correct: very high confidence at least 9 out of 10; high confidence about 8 out of 10; medium confidenceabout 5 out of 10.Where uncertainty in specific outcomes is assessed using expert judgment and statistical analysis of a body of evidence (e.g. observations or model results), then the following likelihood ranges are used to express the assessed probability of occurrence: virtually certain >99%; extremely likely >95%; very likely >90%; likely >66%;.

IPCC Emissions and Equilibrium Temperatures

IPCC Temperature projections

Is a Hotter Sun the Culprit?

Since 1975• Troposphere has warmed• Stratosphere has cooled

This is not what a hotter sun would do

Changing Ocean Currents

Global warming could alter ocean currents and cause both excessive warming and severe cooling.

Ocean Acidification

Click for Ocean Acidification Network

Click for NRDC Acid Test

FACTORS AFFECTING THE EARTH’S TEMPERATURE

Some factors can amplify (positive feedback) and some can dampen (negative feedback) projected global warming.

There is uncertainty about how much CO2 and heat the oceans can remove from the troposphere and how long the heat and CO2 might remain there.

There Is Uncertainty about the Effects of Cloud Cover on Global Warming

Warmer temperatures create more clouds• Thick, light-colored low altitude clouds: decrease

surface temperature• Thin, cirrus clouds at high altitudes: increase

surface temperature

Outdoor Air Pollution Can Temporarily Slow Global Warming

Aerosol and soot pollutants• Will not enhance or counteract projected global

warming• Fall back to the earth or are washed out of the

lower atmosphere• Reduction: especially in developed countries

DEALING WITH GLOBAL WARMING

Climate change is such a difficult problem to deal with because:• The problem is global.• The effects will last a long time.• The problem is a long-term political issue.• The harmful and beneficial impacts of climate

change are not spread evenly.• Many actions that might reduce the threat are

controversial because they can impact economies and lifestyles.

19-2 What Are Some Possible Effects of a Warmer Atmosphere?

Concept 19-2 The projected rapid change in the atmosphere's temperature during this century is very likely to increase drought and flooding, shift areas where food can be grown, raise sea levels, result in intense heat waves, and cause the premature extinction of many species.

IPCC Projected Regional Impacts

IPCC ImpactsVery likely = 90% probable

Enhanced Global Warming Could Have Severe Consequences

Tipping point and irreversible climate change

Worst-case scenarios• Ecosystems collapsing• Low-lying cities flooded• Wildfires in forests• Prolonged droughts: grasslands become dust

bowls• More destructive storms• Glaciers shrinking; rivers drying up

Projected Effects of Global Warming and the Resulting Changes in Global Climate

Fig 19-7

Severe Drought Is Increasing: The Browning of the Earth

Accelerate global warming, lead to more drought

Biodiversity will decrease

Net Primary Productivity (NPP) will decrease

Dry climate ecosystems will increase

Ice and Snow Are Melting

Europe’s Alps• Glaciers are disappearing

South America• Glaciers are disappearing

Greenland• Warmer temperatures

Areas of Glacial Ice Melting in Greenland during Summer 1982–2007 Increased

Fig 19-c

Sea Levels Are Rising

Projected irreversible effect• Degradation and loss of 1/3 of coastal estuaries,

wetlands, and coral reefs• Disruption of coastal fisheries• Flooding of • Low-lying barrier islands and coastal areas• Agricultural lowlands and deltas

• Contamination of freshwater aquifers• Submergence of low-lying islands in the Pacific

and Indian Oceans and the Caribbean

Areas of Florida, U.S., to Flood If Average Sea Level Rises by One Meter

Fig19-8

Low-Lying Island Nation: Maldives in the Indian Ocean

Permafrost Is Likely to Melt: Another Dangerous Scenario

Carbon present as CH4 in permafrost soils and lake bottoms

2004: Arctic Climate Impact Assessment• 10–20% of the permafrost might melt this century

Effect on global warming – ice reflects heat, land absorbs heat.

Projected Decline in Arctic Tundra in Portions of Russia from 2004 to 2100

Fig 19-10

Global Warming Is a Major Threat to Biodiversity

Most susceptible ecosystems• Coral reefs• Polar seas• Coastal wetland• High-elevation mountaintops• Alpine and arctic tundra

Effects on Biodiversity: Winners and Losers

Possible effects of global warming on the geographic range of beech trees based on ecological evidence and computer models.

Changes in Average Ocean Temperatures, Relative to Coral Bleaching Threshold

Fig 19-11

Exploding Populations of Mountain Pine Beetles in British Columbia, Canada

Climate Change Will Shift Areas Where Crops Can Be Grown

Regions of farming may shift• Decrease in tropical and subtropical areas• Increase in northern latitudes• Less productivity; soil not as fertile

Genetically engineered crops more tolerant to drought

Climate Change Will Threaten the Health of Many People

Deaths from heat waves will increase

Deaths from cold weather will decrease

Higher temperatures can cause• Increased flooding

• Increase in some forms of air pollution, more O3

• More insects, microbes, toxic molds, and fungi

19-3 What Can We Do to Slow Climate Change? (1)

Concept 19-3A To slow the rate of global warming and climate change, we can increase energy efficiency, sharply reduce greenhouse gas emissions, rely more on renewable energy resources, and slow population growth.

DEALING WITH GLOBAL WARMING

Climate change is such a difficult problem to deal with because:• The problem is global.• The effects will last a long time.• The problem is a long-term political issue.• The harmful and beneficial impacts of climate

change are not spread evenly.• Many actions that might reduce the threat are

controversial because they can impact economies and lifestyles.

19-3 What Can We Do to Slow Climate Change? (2)

Concept 19-3B Governments can subsidize energy efficiency and renewable energy use, tax greenhouse gas emissions, set up cap-and-trade emission reduction systems, and help to slow population growth.

DEALING WITH GLOBAL WARMING

Two ways to deal with global warming:• Mitigation that reduces greenhouse gas emissions.• Adaptation, where we recognize that some warming

is unavoidable and devise strategies to reduce its harmful effects.

DEALING WITH GLOBAL WARMING

Governments can tax greenhouse gas emissions and energy use, increase subsidies and tax breaks for saving energy, and decrease subsidies and tax breaks for fossil fuels.

A cash program to slow and adapt to global warming now is very likely to cost less than waiting and having to deal with its harmful effects later.

Avoiding Catastrophe: We Can Reduce the Threat of Climate Change

Input or prevention strategies

Improve energy efficiency to reduce fossil fuel use

Stop cutting down tropical forests

Output strategy• Capture and store CO2

IPCC Climate Change Model

Fig. 19-13, p. 515

SOLUTIONS

Global Warming

Prevention CleanupCut fossil fuel use (especially coal)

Remove CO2 from smokestack and vehicle emissionsShift from coal to natural gas Store (sequester) CO2 by planting treesImprove energy efficiencySequester CO2 deep underground (with no leaks allowed)

Shift to renewable energy resources

Transfer energy efficiency and renewable energy technologies to developing countries

Sequester CO2 in soil by using no-till cultivation and taking cropland out of production

Reduce deforestation Sequester CO2 in the deep ocean (with no leaks allowed)

Use more sustainable agriculture and forestry

Repair leaky natural gas pipelines and facilitiesLimit urban sprawl

Reduce poverty Use animal feeds that reduce CH4 emissions from cows (belching)

Slow population growth

International Climate Negotiations: The Kyoto Protocol

– Treaty on global warming which first phase went into effect January, 2005 with 189 countries participating.

– It requires 38 participating developed countries to cut their emissions of CO2, CH4, and N2O to 5.2% below their 1990 levels by 2012.

– Developing countries were excluded.• The U.S. did not sign, but California and Maine

are participating.• U.S. did not sign because developing countries

such as China, India and Brazil were excluded.

Fifteen Ways to Cut CO2 Emissions

Fig. 19-14, p. 515

Stepped Art

Some Output Methods for Removing CO2 from the Atmosphere and Storing It

Fig19-15

Case Study: Is Capturing and Storing CO2 the Answer?

Problems with carbon capture and storage cont…• Promotes the continued use of coal (world’s

dirtiest fuel)• Effect of government subsidies and tax breaks

• Stored CO2 would have to remain sealed forever: no leaking. This is book’s opinion. Flint does not agree

Some Governments Are Leading the Way

Costa Rica: goal to be carbon neutral by 2030

Norway: aims to be carbon neutral by 2050

China and India must change energy habits

U.S. cities and states taking initiatives to reduce carbon emissions

What Can You Do? Reducing CO2 Emissions

Fig 19-16

We Can Prepare for the Harmful Effects of Climate Change?

Genetically engineer crops more tolerant to drought

Stockpile 1–5 years of key foods

Waste less water

Connect wildlife reserves with corridors

Ways to Prepare for the Possible Long-Term Harmful Effects of Climate Change

Fig19-17

19-4 How Have We Depleted O3 in the Stratosphere and What Can We Do?

Concept 19-4A Widespread use of certain chemicals has reduced ozone levels in the stratosphere, which allows for more harmful ultraviolet radiation to reach the earth’s surface.

Concept 19-4B To reverse ozone depletion, we must stop producing ozone-depleting chemicals and adhere to the international treaties that ban such chemicals.

Fig. 19-18, p. 523

300

290

280

270

Mea

n T

ota

l O

zon

e L

evel

(D

ob

son

un

its)

1970 1980 1990 2000 2010

260

Year

Natural Capital Degradation: Massive Ozone Thinning over Antarctica in 2007

Fig 19-19

Science Focus: Rowland and Moline—A Scientific Story of Courage and Persistence

Research• CFCs are persistent in the atmosphere• Rise into the stratosphere over 11-20 years• Break down under high-energy UV radiation• Halogens produced accelerate the breakdown of

O3 to O2

• Each CFC molecule can last 65-385 years

1988: Dupont stopped producing CFCs

Summary of CFCs and Other Chlorine-Containing Compounds that Destroy Ozone

Fig19-d

Natural Capital Degradation: Effects of Ozone Depletion

Fig 19-20

Structure of the Human Skin and the Relationship between UV and Skin Cancer

Fig 19-e

Thin layer of dead cells

Squamous cells Epidermis

Basal layer Sweat gland

Melanocyte cellsDermis

Blood vesselsBasal cell

Hair

This long-wavelength (low-energy) form of UV radiation causes aging of the skin, tanning, and sometimes sunburn. It penetrates deeply and may contribute to skin cancer.

This shorter-wavelength (high-energy) form of UV radiation causes sunburn, premature aging, and wrinkling. It is largely responsible for basal and squamous cell carcinomas and plays a role in malignant melanoma.

Ultraviolet A Ultraviolet B

Fig. 19-E, p. 526

Stepped Art

Basal Cell Carcinoma MelanomaSquamous Cell Carcinoma

Human Health• Worse sunburn• More eye cataracts• More skin cancers• Immune system suppression

Food and Forests• Reduced yields for some crops• Reduced seafood supplies from reduced phytoplankton• Decreased forest productivity for UV-sensitive tree species

Wildlife• Increased eye cataracts in some species• Decreased population of aquatic species sensitive to UV radiation• Reduced population of surface phytoplankton• Disrupted aquatic food webs from reduced phytoplankton

Air Pollution and Materials• Increased acid deposition• Increased photochemical smog• Degradation of outdoor paints and plastics

Global Warming

• Accelerated warming because of decreased ocean uptake of CO2 from atmosphere by phytoplankton and CFCs acting as greenhouse gases

Effects of Ozone DepletionNatural Capital Degradation

Fig 19-20

What Can You Do? Reducing Exposure to UV Radiation

Fig 19-f

We Can Reverse Stratospheric Ozone Depletion

Stop producing all ozone-depleting chemicals

60–100 years of recovery of the O3 layer

1987: Montreal Protocol

1992: Copenhagen Protocol

Ozone protocols: prevention is the key

Animation: How CFCs destroy ozone